1. Field of the Invention
This invention relates to a recording method and a recording apparatus in which recording elements are driven for heat generation to thereby accomplish recording.
The term "recording apparatus" covers, for example, a typewriter, a copying apparatus, a printer and a facsimile apparatus. Also, the recording system to which the present invention is applicable and in which recording elements are driven for heat generation to thereby accomplish recording covers the so-called ink jet recording system, the heat transfer recording system, the thermosensitive recording system and the electrical energization recording system.
2. Related Background Art
A facsimile apparatus to which a thermal printer using the thermosensitive recording system is applied as a recording apparatus will hereinafter be described as an example.
In the recent thermal printers, the heat generating elements of the thermal head are higher in density and precision and designed to be able to record with smaller applied energy. Thus, the heat generating elements of the thermal head have become able to record in quick response to applied energy, but tends to cool down immediately when the application of the energy is stopped. As is well known, in the printing on thermosensitive paper in the thermal printer, the color forming area of the recording paper is varied by the amount of energy applied to the thermal head, and this is affected also by the amount of heat accumulated in the thermal head.
That is, if energy is applied continuously at a predetermined period, the color forming area is stable, but if the period of application of energy becomes long or the downtime of the thermal head becomes long, the thermal head is cooled down, and this leads to the possibility that even if the same energy is applied, the color forming area of the recording paper becomes smaller than the usual color forming area. Also, if the applied energy is set to a great amount with the lengthening of the period of application taken into account, there is the problem that when the thermal head is driven for heat generation at a predetermined period, the color forming area becomes large and the image recording density becomes non-uniform.
However, in the recent recording apparatus having more functions, the period of input of printing data tends to become non-uniform and therefore, such design observing a predetermined recording period strictly is becoming difficult. For example, when a trouble occurs during the reception of recording information, recording is once stopped, and recording is resumed after complete reception of the recording information. This sometimes gives rise to the irregularity of downtime. For this reason, there is a method of preventing the cooling of the thermal head by applying energy to the thermal head again to thereby re-drive the thermal head when the recording period or the downtime has become long, but there has been the problem that if the print timing of the next line occurs during the re-driving, the completion of the re-driving for one line must be waited for and thus the recording time becomes long.